Authorities in Alaska's largest city say three first-graders have been disciplined over a plot to kill a fellow student with silica gel packets that the girls believed was poison.

Parents of the 32 first-graders attending Winterberry Charter School in Anchorage got word of the plot in an email Tuesday. School district officials say the students acknowledged they planned the poisoning.

Police say a school resource officer interviewed the girls and charges won't be filed. Silica gel packets, which soak up moisture, aren't poisonous.

Discipline was left up to the school district. The email says it entailed "significant consequences." Spokeswoman Heidi Embley says she couldn't release further details.

Police say the plot emerged from an ongoing feud.

Principal Shanna Mall told Anchorage television station KTUU that the students were suspended. Mall couldn't immediately be reached for comment Wednesday.